Automated storage and retrieval system and methods

ABSTRACT

A method for operating an automated storage and retrieval system includes transferring a first item storage container from an aisle to a first region of a first storage location, positioning a second item storage container in the aisle proximate the first item storage container, interlocking the second item storage container to the first item storage container by engaging a releasable coupling structure extending there between, and applying, in a first direction transverse to the aisle, a force to the second item storage container sufficient in magnitude and duration to cause the first item storage container to occupy the second region of the first storage location and the second item storage container to occupy the first region of the first storage location, whereby the first and second item storage containers remain interlocked while in the first storage location.

PRIORITY CLAIM

This application is a continuation of co-pending U.S. patent applicationSer. No. 15/905,783 filed Feb. 26, 2018. This application also claimspriority to U.S. Provisional Patent Application No. 62/463,399 filed onFeb. 24, 2017. The entire disclosure of each of the foregoingapplications is hereby incorporated herein by reference.

TECHNICAL FIELD

This disclosure relates to material handling systems and, moreparticularly, to systems and methods for storing items within parallel,vertical arrays of storage locations.

BACKGROUND

Storing items and retrieving items (e.g., to fill discrete customerorders) can be laborious and time consuming. Many large organizationshave extensive storage areas in which numerous and diverse items arestored and/or from which they are retrieved. Sorting and retrievingitems from the hundreds or thousands of storage areas requiressignificant labor to perform manually.

By way of illustrative example, some automated storage and retrieval(ASR) systems utilize one or more three dimensional rack structureswherein each defines a first array of storage spaces and a second arrayof storage spaces. In such systems, the rack structure defines an aislewhich extends the length and height of the two storage space arrays sothat a storage container can be individually transported to, andinserted into, any vacant storage space of either array. Conversely, anystorage container already disposed in one of the storage spaces ofeither array can be extracted and transported to a remote destinationsuch, for example, as a picking station where a worker picks items fromthe storage containers.

SUMMARY OF THE INVENTION

Embodiments of the present disclosure are directed to automated storageand retrieval systems and methods by which item-containing storagecontainers are removed from and restored to storage positions which aremore densely arranged than has heretofore been possible at a comparablerate of throughput.

In embodiments, a plurality of detachably coupled storage containers areinterlocked together, one behind the other(s), until any one of them isto be retrieved from a single storage location of an array of storagelocations. Such in-situ interlocking permits two or more storagecontainers to be stored, as a group, in a space-efficient manner withina single, aisle-facing storage space location. As well, withdrawal of anaisle-facing storage container from a storage location causes anyremaining interlocked storage container(s) of the same group to advancetoward the aisle as part of the same operation. Interlocking containersin accordance with the present disclosure therefore obviates the needfor a complex, multiple-container gripping structure having the abilityto move all containers at the same time and/or the need to repositionthe containers in sequence in order to expose a needed container of agroup.

According to one embodiment, a method for operating an automated storageand retrieval system comprises transferring a first item storagecontainer, from an aisle of a rack structure defining parallel arrays ofstorage locations accessible from the aisle, to a first region of afirst storage location proximal to the aisle; positioning a second itemstorage container in the aisle proximate the first item storagecontainer; interlocking the second item storage container to the firstitem storage container using a releasable coupling structure extendingthere between; and applying, in a first direction transverse to theaisle, a force to the second item storage container sufficient inmagnitude and duration to cause the first item storage container tooccupy a second region of the first storage location and the second itemstorage container to occupy the first region of the first storagelocation, whereby the first and second item storage containers remaininterlocked while in the first storage location.

According to an aspect of the method, the transferring includestransporting the first item storage container within the aisle and intoa position of alignment with the first storage location.

According to another aspect of the method, the transferring furtherincludes, after transporting the first item storage container within theaisle, applying a force to the first item storage container sufficientin magnitude and duration to cause the first item storage container tooccupy the first region of the first storage location.

According to a further aspect of the method, forces are applied in thefirst direction to a surface of the first item storage container.

According to a further aspect of the method, the transporting isperformed by operating a first independently movable vehicle, of aplurality of independently movable vehicles, to move at least one ofhorizontally or vertically within the aisle and into a position ofalignment with the first storage location.

According to a further aspect of the method, wherein the transferringfurther includes operating the first independently movable vehicle toapply a force to the first item storage container sufficient inmagnitude and duration to cause the first item storage container tooccupy the first region of the first storage location.

According to a further aspect of the method, a second independentlymovable vehicle, of the plurality of independently movable vehicles, ismoved at least one of horizontally or vertically within the aisle andinto a position aligning a releasable coupling component of the seconditem storage container with a releasable coupling component of the firstitem storage container.

According to a further aspect of the method, interlocking of the firstand second item storage containers is performed by operating the secondindependently movable vehicle to move into a position bringing thereleasable coupling component of the second item storage container intointerlocking engagement with the releasable coupling component of thefirst item storage container.

According to a further aspect of the method, the second independentlymovable vehicle is operated to apply forces to the second item storagecontainer while the releasable coupling component of the second itemstorage container is maintained in interlocking engagement with thereleasable coupling component of the first item storage container.

According to a further aspect of the method, the first independentlymovable vehicle is operated to move into a charging area followingtransfer of the first item storage container to the first storagelocation and the second independently movable vehicle is operated tomove into the charging area following transfer of the second itemstorage container.

According to a further aspect of the method, force is applied to thesecond item storage container in a second direction opposite to thefirst direction, the force applied to the second item storage containerbeing sufficient in magnitude and duration to cause withdrawal of thesecond item container from the first region of the first storagelocation and, at the same time, to cause the first item storagecontainer to move from the second region of the first storage locationinto the first region of the first storage location.

According to a further aspect of the method, the second item storagecontainer is decoupled from the first item storage container bydisengaging the releasable coupling structure extending there between.

According to a further aspect of the method, the second item storagecontainer is transferred to a new destination following decoupling ofthe second item storage container from the first item storage container.

According to a further aspect of the method, the new destination is agoods-to-person pick station and at least one item is one of added to orremoved from the second item storage container.

According to a further aspect of the method, the new destination is thefirst region of a second storage location, and the second item istransferred to the first region of the second storage location bypositioning the second item storage container in the aisle proximate athird item storage container occupying the first region of the secondstorage location; interlocking the second item storage container to thefirst item storage container by engaging a releasable coupling structureextending there between; and applying, in a direction transverse to theaisle, a force to the second item storage container sufficient inmagnitude and duration to cause the third item storage container tooccupy the second region of the second storage location and the seconditem storage container to occupy the first region of the second storagelocation.

According to a further aspect of the method, the second storage locationis selected from among a plurality of storage locations having at leastone vacant storage region, based on shortest distance to the firststorage location.

According to a further embodiment, a method for storing and/orretrieving items by operating an automated storage and retrieval systemcomprises transferring a first item storage container from a first aisleto a first region of a first storage location; positioning a second itemstorage container in the first aisle proximate the first item storagecontainer; releasably coupling the second item storage container to thefirst item storage container; and applying a force to the second itemstorage container sufficient to cause the first item storage containerto occupy a second region of the first storage location behind the firstregion and the second item storage container to occupy the first regionof the first storage location.

According to an aspect of the method for storing and/or retrievingitems, the transferring includes transporting the first item storagecontainer within the first aisle and into a position of alignment withthe first storage location.

According to another aspect of the method for storing and/or retrievingitems, the transferring further includes operating a first independentlymovable vehicle to move the first item storage container into the firstregion of the first storage location.

According to yet another aspect of the method for storing and/orretrieving items, the positioning is performed by operating a secondindependently movable vehicle to align a releasable coupling componentof the second item storage container with a releasable couplingcomponent of the first item storage container.

According to still another aspect of the method for storing and/orretrieving items, the coupling is performed by operating the secondindependently movable vehicle to move the releasable coupling componentof the second item storage container into interlocking engagement withthe releasable coupling component of the first item storage container.

According to another aspect of the method for storing and/or retrievingitems, a third independently movable vehicle is operated within a secondaisle to withdraw the first item container from the first region of thefirst storage location while moving the second item storage containerinto the second region of the first storage location.

According to still another aspect of the method for storing and/orretrieving items, the first item storage container is decoupled from thesecond item storage container by disengaging the releasable couplingstructure extending there between.

According another aspect of the method for storing and/or retrievingitems, the second item storage container is transferred to a newdestination following decoupling of the second item storage containerfrom the first item storage container.

According to still another aspect of the method for storing and/orretrieving items, the new destination is a second storage locationaccessible from the first aisle and a second aisle.

According to another embodiment, a method of retrieving items byoperating an automated storage and retrieval system having a rackstructure for defining parallel arrays of storage locations separated byan aisle, each storage location of an array being accessible from atleast one aisle, comprises disengaging a releasable coupling structureto decouple a first item storage container occupying a first region of afirst storage location from a second item storage container occupying asecond storage region of the first storage location; and transferring adecoupled one of the first item storage container and the second itemstorage container to a new destination following the disengaging.

According to an aspect of the method of retrieving items, thetransferring includes operating an independently movable vehicle, of aplurality of independently movable vehicles, to move the decoupled itemstorage container at least one of horizontally or vertically within afirst aisle.

According to another aspect of the method of retrieving items, the newdestination is the first region of a second storage location, andtransferring the second item to the first region of the second storagelocation comprises positioning the second item storage container in thefirst aisle proximate a third item storage container occupying the firstregion of the second storage location; engaging a releasable couplingstructure to couple the first item storage container to the third itemstorage container; and applying, in a direction transverse to the aisle,a force to the second item storage container sufficient in magnitude andduration to cause the third item storage container to occupy the secondregion of the second storage location and the second item storagecontainer to occupy the first region of the second storage location.

According to yet another aspect, the current invention provides amaterial handling system for storing or retrieving a plurality of items.The system includes three sets of spaced apart racks of storagelocations. A plurality of first vehicles are operable within a firstaisle formed between the first and second racks. The vehicles areoperable to deliver items to and retrieve items from the storagelocations in the first and second storage racks. A plurality of secondvehicles are operable within a second aisle formed between the secondand third racks. The second vehicles are operable to deliver items toand retrieve items from the storage locations in the second and thirdstorage racks. The second rack is configured so that an item deliveredto the second rack by one of the second vehicles can be retrieved fromthe second rack by one of the first vehicles. Optionally, the systemincludes a first track positioned adjacent a first side of the firstrack, a second track positioned adjacent a first side of the secondrack, a third track positioned adjacent a second side of the second rackand a fourth track positioned adjacent a first side of the third rack.The first and second tracks may guide the first vehicles around a loopin the first aisle and the third and fourth tracks may guide thevehicles around a loop in the second aisle. Additionally, each of thefirst, second third and fourth tracks may comprise a plurality ofvertical track sections interconnected by a plurality of horizontaltrack sections. Further, each of the first, second and third racks maycomprise an array of storage locations.

Optionally, the storage locations of the first, second or third storagerack is configured to accommodate a plurality of storage containers.Additionally, each of the storage containers may comprise one or morereleasable connectors configured to releasably connect two storagecontainers. The releasable connection may allow the two storagecontainers to be connected to one another when the two storagecontainers are stored within one of the storage locations.

Optionally, the first vehicles may include a first transfer mechanismconfigured to transfer items into the storage locations in the secondrack and the second vehicles may include a second transfer mechanismconfigured to transfer items from the storage locations in the secondrack onto the second vehicles.

Optionally, a first picking station may be positioned along the firstaisle wherein the first aisle is configured so that the first vehiclesare able to retrieve items from the first or second racks and deliverthe items to the first picking station. Additionally, a second pickingstation may be positioned along the second aisle wherein the secondaisle is configured so that the second vehicles are able to retrieveitems from the second or third racks and deliver the items to the secondpicking station. Further, the second rack may be configured so thatitems transferred to the second rack from one of the vehicles in thesecond aisle may be retrieved by one of the first vehicles in the firstaisle and delivered to the first picking station so that items from thesecond aisle can be transferred to the first aisle and delivered to thefirst picking station.

Optionally, the first and second vehicles are independently operableself-propelled vehicles. Additionally, the first vehicles may beconstrained to movement within the first aisle and the second vehiclesmay be constrained to movement within the second aisle. Further, thefirst rack may comprise a first array of bins disposed in a plurality ofrows or columns, the second rack may comprise a second array of binsdisposed in a plurality of rows or columns, and the third rack maycomprise a third array of bins disposed in a plurality of rows orcolumns.

According to yet another aspect, the present invention provides a methodfor operating an automated storage and retrieval system. The methodincludes the step of conveying a first vehicle through a first aislebetween a first rack of storage locations and a second rack of storagelocations and conveying a second vehicle through a second aisle betweenthe second rack of storage locations and a third rack of storagelocations. An item is transferred from one of the storage location onthe first rack to the first vehicle and the item is transferred from thefirst vehicle to a storage location on the second rack. The item istransferred from the second rack to the second vehicle and thentransferred from the second vehicle to one of the storage locations onthe third rack. Optionally, the step of conveying a first vehiclecomprises driving the first vehicle along a first track adjacent thefirst rack and a second track adjacent the second rack and the step ofconveying a second vehicle comprises driving the second vehicle along athird track adjacent a second side of the second rack and a fourth trackadjacent the third rack. Additionally, the step of conveying a firstvehicle may comprise driving the first vehicle around a first bop formedof a first plurality of generally vertical tracks connected with a firstplurality of generally horizontal tracks and the step of conveying asecond vehicle may comprise driving the second vehicle around a secondloop formed of a second plurality of generally vertical tracks connectedwith a second plurality of generally horizontal tracks.

Optionally, the method includes the step of conveying the secondvehicle_ and the item to a picking station positioned along the secondaisle and presenting the item to an operator at the picking station.

Optionally, the item comprises a first storage container having areleasable connector and the method comprises the step of releasablyconnecting the first storage container with a second storage containerlocated in the second rack. The method may also include the step ofdisplacing the first storage container in the rack by displacing thesecond storage container connected to the first storage container.Additionally, the method may include the step of disconnecting thesecond storage container from the second storage container. The step ofdisconnecting may comprise displacing the first container relative tothe second container.

Optionally, the step of transferring the item from the first vehicle toa storage location on the second rack may include the steps of aligningthe first vehicle with the storage location on the second rack andoperating a first transfer mechanism on the first vehicle to transferthe item to the storage location. Additionally, the step of transferringthe item from the storage location on the second rack may include thesteps of aligning the second vehicle with the storage location andoperating a second transfer mechanism on the second vehicle to transferthe item to the second vehicle.

Optionally, the step of conveying a first vehicle through a first aislemay comprise constraining the first vehicle to travel within the firstaisle and the step of conveying a second vehicle through a second aislemay comprise constraining the second vehicle to travel within the secondaisle.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing summary and the following detailed description of thepreferred embodiments of the present invention will be best understoodwhen read in conjunction with the appended drawings, in which:

FIG. 1 is a perspective view of a single aisle, automated storage andretrieval (ASR) system according to one or more embodiments consistentwith the present disclosure;

FIG. 2A is a fragmentary top view of the exemplary single-aisle ASRsystem of FIG. 1, taken across reference plane IIA-IIA of FIG. 1 anddepicting left and right arrays of storage locations as well as thehorizontal movement of an item storage container within the aisle thatextends between the arrays, according to one or more embodiments;

FIG. 2B, is a fragmentary side view of the single-aisle ASR embodimentdepicted in FIG. 1, taken in elevation across the reference planeIIB-IIB of FIG. 1 and illustrating the vertical arrangement of storagelocations in two arrays of storage locations;

FIG. 3A is a fragmentary side view of the single-aisle ASR embodimentdepicted in FIG. 1, taken in elevation across the reference planeIII-III of FIG. 1 and exemplifying a network of vertical and horizontaltracks arranged along each side of the aisle in accordance with one ormore embodiments;

FIG. 3B is an enlarged perspective view of a vehicle dimensioned andarranged for independent movement within the aisle of the ASR embodimentdepicted in FIG. 1 (e.g., along the tracks depicted in FIG. 2);

FIG. 4 is an enlarged perspective view of a gate of the trackarrangement illustrated in FIG. 2;

FIG. 5 is an enlarged perspective view of a gate of the trackarrangement illustrated in FIG. 2;

FIG. 6 is an enlarged perspective view of a gate of the trackillustrated in FIG. 2;

FIG. 7 is an enlarged fragmentary view of a wheel of the vehicleillustrated in FIG. 3 and a portion of the track illustrated in FIG. 2;

3 and a portion of the track illustrated in FIG. 2;

FIG. 8 is a side diagrammatic view of a plurality of storage locationsof the apparatus illustrated in FIG. 1;

FIG. 9 is diagrammatic side view of storage containers in the storagelocations of the apparatus illustrated in FIG. 1;

FIG. 10A is a diagrammatic view of the storage containers illustrated inFIG. 9, showing a step in the process of moving a storage container fromone location to another;

FIG. 10B is a diagrammatic view of the storage containers illustrated inFIG. 9, showing a step in the process of moving a storage container fromone location to another;

FIG. 10c is a diagrammatic view of the storage containers illustrated inFIG. 9, showing a step in the process of moving a storage container fromone location to another;

FIG. 10D is a diagrammatic view of the storage containers illustrated inFIG. 9, showing a step in the process of moving a storage container fromone location to another;

FIG. 10E is a diagrammatic view of the storage containers illustrated inFIG. 9, showing a step in the process of moving a storage container fromone location to another;

FIG. 10F is a diagrammatic view of the storage containers illustrated inFIG. 9, showing a step in the process of moving a storage container fromone location to another;

FIG. 10G is a diagrammatic view of the storage containers illustrated inFIG. 9, showing a step in the process of moving a storage container fromone location to another;

FIG. 10H is a diagrammatic view of the storage containers illustrated inFIG. 9, showing a step in the process of moving a storage container fromone location to another;

FIG. 11 is a fragmentary perspective view of a portion of a storage rackof the apparatus illustrated in FIG. 1;

FIG. 12 is a fragmentary perspective view of a portion of a storage rackof the apparatus illustrated in FIG. 1 including a vehicle of theapparatus; and

FIG. 13 is a fragmentary side view of a releasable connection betweenstorage containers of the apparatus illustrated in FIG. 1, in which thestorage containers are connected;

FIG. 14 is a fragmentary side view of a releasable connection betweenstorage containers of the apparatus illustrated in FIG. 1, in which thestorage containers are disconnected;

FIG. 15A is a side elevational view of a multiple aisle ASR systemconstructed in accordance with an exemplary embodiment consistent withthe present disclosure, illustrating a first storage container on avehicle in a first aisle;

FIG. 15B is a side elevational view of the multiple aisle ASR systemillustrated in FIG. 15A, illustrating the first storage container in asecond position in the first aisle;

FIG. 15C is a side elevational view of the multiple aisle ASR systemillustrated in FIG. 15B, illustrating the first storage containertransferred to a storage location;

FIG. 15D is a side elevational view of the multiple aisle ASR systemillustrated in FIG. 15C, illustrating a second storage containertransferred to the storage location;

FIG. 15E is a side elevational view of the multiple aisle ASR systemillustrated in FIG. 15D, illustrating the first storage containertransferred aligned with a second vehicle in a second aisle;

FIG. 15F is a side elevational view of the multiple aisle ASR systemillustrated in FIG. 15E, illustrating the first storage containertransferred to a second vehicle in a second aisle;

FIG. 16 is a side elevational view of a multiple aisle ASR systemconstructed in accordance with yet another embodiment consistent withthe present disclosure.

FIG. 17 is a side elevational view of a multiple aisle ASR systemconstructed in accordance with another embodiment consistent with thepresent disclosure.

DETAILED DESCRIPTION

Embodiments of the present disclosure are directed to automated storageand retrieval systems and methods in which a plurality of detachablycoupled storage containers are interlocked together in seriatim to formgroups of n storage containers, with each respective group being storedwithin a corresponding storage location of at least one array of storagelocations. When one of the storage containers of an interlocked group ofstorage containers is to be retrieved from storage, one or moredecoupling operations and, optionally, container withdrawaloperation(s), are performed until the selected storage container isready for transport to a second location (e.g., a pick station).

In-situ interlocking in accordance with some embodiments of the presentdisclosure permits groups of n storage containers (where n is an integergreater than 1) to be efficiently stored within adjacent racks, whereeach respective rack defines a corresponding array of storage locationsand the storage locations of adjacent racks are separated by an aisle.Withdrawing an aisle-facing storage container from one of the storagelocations of a rack causes any interlocked storage container(s) of thesame group to advance toward the aisle as part of the same withdrawaloperation. If the withdrawn aisle-facing storage container is acontainer selected for retrieval, it is decoupled from the container(s)remaining within the storage location and then transported directly to,for example, a pick station where one or more items are removed from aretrieved storage container. If the aisle-facing container withdrawn anddecoupled initially is not the container selected for retrieval, it istransported to an alternate storage location (e.g., a different storagelocation of the same or a different array). The withdrawal and, ifapplicable, decoupling processes are repeated until the containerselected for retrieval has been withdrawn and decoupled from any othercontainers still remaining in the storage location. Accordingly, complexand costly gripping structures capable of simultaneously gripping,withdrawing, reordering and/or returning multiple containers to astorage location are not required.

Referring now to the figures in general and to FIG. 1 specifically,there is shown a perspective view of an exemplary, single aisle,automated storage and retrieval (ASR) system 10 according to one or moreembodiments consistent with the present disclosure. The system 10includes a conveyor for transporting storage containers 80 between, forexample, one or more storage locations and/or between a storage locationand an item pick station and/or a container transfer station. Anexemplary pick station is indicated generally at reference numeral 300.

In the exemplary embodiment of FIG. 1, the conveyor includes a pluralityof independently movable vehicles 200 which are respectively movablealong dynamically configurable paths to accommodate storage of times inand/or retrieval of items from a storage location of the ASR 10. Othernon-limiting examples of conveyors suitable for use in embodimentsconsistent with the present disclosure include gantry structures,articulating grippers, and any other system capable of moving anindividual container in three, orthogonal directions (i.e., verticallyand horizontally within an aisle and toward and away from a selectedstorage location adjacent to the aisle).

In some embodiments consistent with the present disclosure, the storagecontainers 80 are dimensioned and arranged to receive items managed asinventory using ASR system 10. One or more dividers (not shown) may bepositioned within some or all of the storage containers 80 to subdividethe interior space of each storage container into discrete compartments.The storage containers may have a uniform width W, height H and lengthL. In alternative embodiments (not shown), however, a first subset ofthe storage containers may have a first length L₁ and a second subset ofthe storage containers may have a second length L₂, which may be eithergreater than or less than L₁.

Storage Racks

The storage containers 80 are dimensioned and arranged so that they maybe introduced into (and withdrawn from) a storage location selectablefrom among one or more array(s) of storage locations. By way ofillustrative example, each of the storage rack structures 35 and 40depicted in FIG. 1 may include a network of parallel rails or L-channels(not shown) dimensioned and arranged to define weight bearing supportsurfaces alignable with one or more surfaces of the storage containers80. In such embodiments, a pushing force or pulling force exerted upon afirst storage container of an interlocked group of storage containerscauses all of the storage containers of an interlocked group to slide inthe same direction as the applied force.

In at least one of the rack structures (e.g., rack structure 40), thestorage locations 50 are dimensioned and arranged to accommodate nstorage containers 80 interlocked together and placed one behind theother to form a discrete group, where n is an integer equal to orgreater than two, such that the storage locations have an effectivelength L_(E) of n×L. In addition, or alternatively, the effective lengthL_(E) of the storage locations defined by one or both rack structure(s)may be (r×L₁)+(s+L₂), where each of r and s have an integer value equalto or greater than one.

Turning briefly to FIG. 2A, there is shown a fragmentary top view of theexemplary single-aisle ASR system of FIG. 1, taken across referenceplane IIA-IIA of FIG. 1. In the exemplary embodiment of FIG. 2A, thereare shown left and right arrays of storage locations separated by aisle20, of which only the uppermost storage locations accessible from aisle20 are shown. Each storage location of the exemplary embodiment of FIG.2A defines two storage regions—an aisle-facing, first storage region anda distal, second storage region located directly behind the firststorage region. As such, the uppermost layer of the array defined byrack structure 35 includes aisle-facing regions L_(1A-1) to L_(nA-1) anddistal storage regions L_(1B-1) to L_(nB-1). Likewise, the uppermostlayer of the array defined by rack structure 40 includes aisle-facingregions R_(1A-1) to R_(nA-1) and distal storage regions R_(1B-1) toR_(nB-1).

With continuing reference to FIG. 2A, it will be seen that an exemplarytransport path extends from pick station 300, where items may be picked,sorted and/or transferred from or to containers 80, to a selectedstorage location such as the storage location comprising aisle-facingfirst storage region L_(4A-1) and distal storage region L_(4B-1) ofstorage rack structure 35. As will be described in greater detailshortly, FIG. 2A also depicts portions of a container/vehicle transportpath which is defined, at least in part, by front and rear, verticaltrack segments 130 which, collectively guide the movement of vehicle 200in a downward, vertical direction. So guided, vehicle 200 may be movedinto a position adjacent to one of the aisle-facing storage regions inthe fourth column of the array defined by rack structure 35 (i.e., thecolumn that includes storage regions L_(4A-1) and L_(4B-1)) or in thefourth column of the array defined by rack structure 40 (i.e., thecolumn that includes storage regions R_(4A-1) and R_(4B-1)).

Turning now to FIG. 2B, there is shown a fragmentary side view of thesingle-aisle ASR embodiment depicted in FIG. 1, taken in elevationacross the reference plane IIB-IIB of FIG. 1 and illustrating thevertical arrangement of storage locations in each array of the storagelocations defined by racks 35 and 40. FIG. 2B also depicts portions of acontainer/vehicle transport path which is defined, at least in part, byupper horizontal track segments 135, vertical track segments 130, andlower horizontal track segments 14 which, collectively guide themovement of vehicle 200 to, for example, a position adjacent toaisle-facing storage regions L_(4A-1) and R_(4A-1). In the exemplaryembodiment of FIG. 2B, the empty vehicle 200 is moved from the dottedline position P₁ to the position P₂ which a container 80 is retrievedfrom the aisle-facing storage region L₄₋₁.

Conveyor Arrangement

Turning now to FIG. 3A, there is shown a fragmentary side view of theexemplary, single-aisle ASR system 10 depicted in FIG. 1, taken inelevation across the reference plane III-III and exemplifying anillustrative conveyor system that includes a track network (“track”) 110comprising vertical track segments 130, horizontal track segments 135,and transitional track segments 315 arranged along each side of theaisle 20 in accordance with one or more embodiments, gating mechanismsfor dynamic configuration of transport paths, and independently movablevehicles 200.

Track

Track 110 provides one or more pathways within the aisle 20 (FIGS. 1 and2) for the vehicles 200 to travel to storage locations in the rackstructures 35 and 40. For instance, an embodiment may include a fronttrack 115 adjacent a front rack 35 on one side of the aisle. A reartrack 120 adjacent a rear rack 40 may be spaced apart from the fronttrack 115 to form the aisle 20. The vehicles 200 may move within theaisle 20 along the track. For instance, the vehicle may be supported byone or more front wheels that engage the front track 115 and one or morerear wheels that engage the rear track 120.

As indicated above, each of storage racks 35 and 40 provides a pluralityof storage locations 50 for storing containers 80 that store variousitems. The vehicles 200 move along the track 110 to storage locations.At a storage location 50, a vehicle can transfer a storage container 80from the vehicle into one of the storage locations. Similarly, thevehicle can transfer a storage container 80 from one of the storagelocations onto the vehicle. Additionally, the system may be configuredso that the vehicle transfers a storage container 80 from the vehicle200 to a storage location while at the same time transferring acontainer 80 from a different storage location onto the vehicle 200. Thestorage locations may be arranged as an array of locations adjacent theaisle. Additionally, as discussed further below, the racks 35, 40 mayprovide storage depth so that the storage containers may be stored twoor more deep to increase the storage density of the storage containers80 in the racks.

Independently Movable Vehicles

FIG. 3B is an enlarged perspective view of a vehicle dimensioned andarranged for independent movement within the aisle of the ASR embodimentdepicted in FIG. 1 (e.g., along the tracks depicted in FIGS. 2A, 2B and3A). As shown in FIG. 3B, each of the vehicles 200 includes four wheels220: two forward wheel and two rearward wheels. The forward wheels 220ride in the front track, while the rearward wheel ride in the reartrack. It should be understood that in the discussion of the track thefront and rear tracks 115, 120 are similarly configured opposing tracksthat support the forward and rearward wheels 220 of the vehicles.Accordingly, a description of a portion of either the front or reartrack also applies to the opposing front or rear track.

In embodiments consistent with the present disclosure, each vehicle 200is a semi-autonomous vehicle that includes an onboard drive system andan onboard power supply. In some embodiments, each vehicle furtherincludes a mechanism for inserting item storage containers as containers80 into one of storage locations 50 (FIG. 1) or withdrawing an itemstorage container from one of the storage locations 50. As will soon bedescribed in detail by reference to FIGS. 4-6, each vehicle mayoptionally include a gate actuator 230 for selectively actuating thegates 180 (FIGS. 4-6) to allow the vehicle to selectively changedirection.

The vehicles 200 may incorporate any of a variety of mechanisms forloading an item onto the vehicle and discharging the item from thevehicle into one of the bins. Additionally, the loading/unloadingmechanism 210 may be specifically tailored for a particular application.In the present instance, the loading/unloading mechanism 210 maycomprise a displaceable element configured to engage a container storedat a storage location 190 and pull the item onto the vehicle. Morespecifically, in the present instance, the vehicle includes adisplaceable element configured to move toward a container 80 in anoccupied storage location 50.

After the displaceable element engages the container 80, thedisplaceable element is displaced away from an occupied storage location50, thereby exerting a pulling force of sufficient magnitude anddirection to withdraw a container from an occupied, aisle facing storageregion onto the vehicle 200.y, As will be described in detail shortly,If the withdrawn container is already linked to another container withinthe same storage location, then a preliminary coupling operation isperformed before the withdrawn container is transferred to anotherlocation (e.g., a pick station or alternate storage location of the sameor a different array). Conversely, operation of the displaceable elementin the reverse direction exerts a pushing force of sufficient magnitudeand duration to transfer a storage container from a load bearing surfaceof vehicle 200 into the aisle storage location. If the aisle facingstorage region of a storage location is already occupied, but the onebehind it is not, then a preliminary coupling operation is performed.

In an exemplary embodiment, the loading/unloading mechanism 210 maycomprise a displaceable rod or bar 212. The bar 212 may extend acrossthe width of the vehicle 200 and both ends may be connected with drivechains that extend along the sides of the vehicle. A motor may drive thechains to selectively move the chain toward or away from storagelocations. For example, as the vehicle approaches a storage location toretrieve a container 80, the chain may drive the rod 212 toward thestorage location so that the bar engages a groove or notch 88 in thebottom of the container 80. The chain then reverses so that the bar 212moves away from the storage location 50. Since the bar is engaged in thenotch 88 in the container, as the bar moves away from the storagelocation, the bar 212 pulls the container onto the vehicle. In this way,the loading/unloading mechanism 210 may be operable to retrieve itemsfrom a storage location. Similarly, to store a container in a storagelocation 50, the chain of the loading/unloading mechanism 210 drives thebar 212 toward the storage location until the container is in theaisle-facing region of a storage location. The vehicle may then movedownwardly to disengage the bar from the container 80, thereby releasingthe container. Alternatively, the loading/unloading mechanism may beconfigured so that the bar 212 is driven downwardly, out of engagementwith the notch 88.

Additionally, since the system 10 includes an array of storage locations50 adjacent the front side of the track 110 and a second array ofstorage locations adjacent the rear side of the track, theloading/unloading mechanism 210 is operable to retrieve and storecontainers in the forward array and the rearward array. Specifically, asshown in FIG. 3B, the loading/unloading mechanism 210 includes two barsspaced apart from one another. One bar is operable to engage containersin the forward array, while the second bar is operable to engagecontainers in the rearward array of storage locations.

The vehicle 200 may include four wheels 220 that are used to transportthe vehicle along the track 110. The wheels 220 may be mounted onto twoparallel spaced apart axles 215, so that two of the wheels are disposedalong the forward edge of the vehicle and two of the wheels are disposedalong the rearward edge of the vehicle.

The vehicle may include an onboard motor for driving the wheels 220.More specifically, the drive motor may be operatively connected with theaxles to rotate the axles 215, which in turn rotates the gears 222 ofthe wheels. The drive system for the vehicle may be configured tosynchronously drive the vehicle along the track. In the presentinstance, the drive system is configured so that each gear is driven ina synchronous manner.

The vehicle 200 may be powered by an external power supply, such as acontact along the rail that provides the electric power needed to drivethe vehicle. However, in the present instance, the vehicle includes anonboard power source that provides the requisite power for both thedrive motor and the motor that drives the load/unload mechanism 210.Additionally, in the present instance, the power supply is rechargeable.Although the power supply may include a power source, such as arechargeable battery, in the present instance, the power supply is madeup of one or more ultracapacitors. The ultracapacitors can accept veryhigh amperage to recharge the ultracapacitors. By using a high current,the ultracapacitors can be recharged in a very short time, such as a fewseconds or less.

The vehicle includes one or more contacts for recharging the powersource. In the present instance, the vehicle includes a plurality ofbrushes, such as copper brushes that are spring-loaded so that thebrushes are biased outwardly. The brushes cooperate with a charging railto recharge the power source.

Each vehicle may include a load sensor for detecting that a container isloaded onto the vehicle. The sensor(s) may be used to detect whether theitem is properly positioned on the vehicle. For instance, the loadsensor may include a force detector detecting a weight change or aninfrared sensor detecting the presence of an item.

The vehicle may further include a processor for controlling theoperation of the vehicle in response to signals received from a centralprocessor of the system. Additionally, the vehicle may include awireless transceiver so that the vehicle can continuously communicatewith the central processor as it travels along the track. Alternatively,in some applications, it may be desirable to incorporate a plurality ofsensors or indicators positioned along the track. The vehicle mayinclude a reader for sensing the sensor signals and/or the indicators,as well as a central processor for controlling the operation of thevehicle in response to the sensors or indicators.

Gating Mechanisms

FIGS. 4-6 are enlarged perspective views respectively depicting gates ofthe track arrangement 110 of FIG. 3A, while FIG. 7 is an enlargedfragmentary view of a wheel of the vehicle illustrated in FIG. 3B and aportion of the track illustrated in FIG. 3A. Referring concurrently toFIGS. 4-7, the details of a track 110 dynamically configurable to definea transport path for conveying containers to or from a storage locationwill be described in greater detail. As noted above, however, it shouldbe appreciated that the illustrated track is merely an exemplary trackthat can be used with the system. The precise configuration may varyaccording to the application and as noted above, the conveyor system maynot include the track or independently movable vehicles as depicted inthe illustrative embodiments.

The track 110 may include an outer wall 152 and an inner wall 154 thatis spaced apart from the outer wall and parallel to the outer wall. Thetrack also may have a back wall 160 extending between the inner andouter walls. As can be seen in FIG. 7, the outer and inner walls 152,154 and the back wall form a channel. The wheels 220 of the vehicle ridein this channel. The track may include both a drive surface 156 and aguide surface 158. The drive surface positively engages the vehicles toenable the vehicle to travel along the track. The guide surface 158guides the vehicle, maintaining the vehicle in operative engagement withthe drive surface 156. In the present instance, the drive surface isformed of a series of teeth, forming a rack that engages the wheels ofthe vehicles as described further below. The guide surface 158 is agenerally flat surface adjacent the rack 156. The rack 156 extendsapproximately halfway across the track and the guide surface 158 extendsacross the other half of the track. As shown in FIGS. 4-7, the rack 156may be formed on the inner wall 154 of the track. The opposing outerwall 152 may be a generally flat surface parallel to the guide surface158 of the inner wall.

As described above, the track 110 may include a plurality of verticalsegments or legs extending between the horizontal upper and lower rails135, 140. An intersection 170 may be formed at each section of the trackat which one of the vertical legs intersects one of the horizontal legs.Each intersection may include an inner branch 172 that is curved and anouter branch 176 that is generally straight. The intersections of thevertical legs with the lower rail incorporate similar intersections,except the intersections are reversed.

Each intersection 170 may include a pivotable gate 180 that may have asmooth curved inner race and a flat outer race that has teeth thatcorrespond to the teeth of the drive surface 156 for the track. The gate180 may pivot between a first position and a second position. In thefirst position, the gate 180 is closed so that the straight outer race184 of the gate is aligned with the straight outer branch 176 of theintersection. In the second position, the gate is open so that thecurved inner race 182 of the gate is aligned with the curved branch 172of the intersection.

Accordingly, in the closed position, the gate is pivoted downwardly sothat the outer race 184 of the gate aligns with the drive surface 156.In this position, the gate blocks the vehicle from turning down thecurved portion, so that the vehicle continues straight through theintersection. In contrast, as illustrated n FIG. 6, when the gate ispivoted into the open position, the gate blocks the vehicle from goingstraight through the intersection. Instead, the curved inner race 182 ofthe gate aligns with the curved surface of the inner branch 172 and thevehicle turns through the intersection. In other words, when the gate isclosed, a vehicle goes straight through the intersection along eitherthe upper rail 130 or the lower rail, depending on the location of theintersection. When the gate is opened, the gate directs the vehicle fromeither a vertical rail to a horizontal rail or from a horizontal rail toa vertical rail, depending on the location of the intersection.

In the foregoing description, the gates allow one of the vehicles toeither continue in the same direction (e.g. horizontally) or turn in onedirection (e.g. vertically). However, in some applications, the systemmay include more than two horizontal rails that intersect the verticalcolumns. In such a configuration, it may be desirable to include adifferent rail that allows the vehicles to turn in more than onedirection. For instance, if a vehicle is traveling down a column, thegate may allow the vehicle to turn either left or right down ahorizontal rail, or travel straight through along the vertical column.Additionally, in some instances, the vehicles may travel upwardly

Since the system 10 includes a number of vehicles 200, the positioningof the vehicles is controlled to ensure that the different vehicles donot crash into each other. In one embodiment, the system 10 uses acentral controller that tracks the position of each vehicle 200 andprovides control signals to each vehicle to control the progress of thevehicles along the track. The central controller may also controloperation of the various elements along the track, such as the gates180. Alternatively, the gates may be actuated by the vehicles 200. Forinstance, referring to FIG. 4-5, the gates 180 may include a passiveactuator 190 that responds to an actuator 230 on the vehicles. If theactuator on the vehicle engages the gate actuator 190 then the gatemoves from a first position to a second position. For instance, as shownin FIG. 4, the gate is in a first position so that the vehicle willremain along the horizontal rail 135. If the gate actuator 230 on thevehicle 200 engages the actuator 190 on the gate, the gate 180 willpivot upwardly into a second position so that the vehicle will turn andmove downwardly along the vertical rail 130.

The actuators 190 on the gates may be moveable actuation surfaces 192connected to the gate by a linkage. For instance, the actuation surface192 may be mounted on a pivotable arm 193. To actuate the gate and moveit from the first position to the second position, the gate actuator 230on the vehicle contacts the actuation surface 192. The actuation surfaceis angled similar to a ramp, so that as the vehicle advances toward thegate, the gate actuator on the vehicle engages the actuation surface andprogressively displaces the arm 193 upwardly. The arm 193 may beconnected to the gate 180 by a linkage. Accordingly, when the arm 193pivots, the gate pivots as well. In this way, the actuator 230 on thevehicle engages the actuator on the gate to move the gate from the firstposition to the second position as shown in FIGS. 4-5. After the vehicle200 passes an open gate, such as shown in FIG. 5, the gate may return tothe closed position shown in FIG. 4. The gate may close automatically,such as by a biasing element or the weight of the gate and/or actuator.

Referring now to FIGS. 8-12, the insertion of containers into thestorage locations 50 of storage racks 35, 40, and/or their withdrawalfor relocation, for example, to an alternate storage location or to apick station, will now be described in greater detail. The storagelocations 50 can be any of a variety of configurations. For instance,the simplest configuration is a shelf for supporting the items or thecontainer holding the items. Similarly, the storage locations 50 mayinclude one or more brackets that cooperate with the storage mechanismto support the storage mechanism in the storage location.

As shown in FIGS. 8 and 11-12, the rack 35 may include a plurality ofvertical supports, such as vertical beams, interconnected with aplurality of horizontal supports, such as horizontal beams. In thepresent instance, the track 110 may form part of the vertical andhorizontal support beams. For instance, the rack 35 may comprise anarray of columns, with each column formed by a plurality of support.Each column may be defined by two front vertical support beams and tworear vertical support beams. As shown in FIG. 11, the front verticalbeams may comprise the vertical legs 130 of the track. Each column mayinclude a plurality of storage areas 50. In particular, each column isseparated into a plurality of aisle facing, first storage regions (orcells) and a plurality of distal, second storage regions (or cells) Eachcell includes a support element for supporting a container to that thecontainer can be stored in the cell. The support elements may be any ofa variety of elements for supporting a container in the storagelocation. For instance, each storage location may include a shelf orother horizontal support onto which a container may be placed. Forinstance, as shown in FIGS. 8 and 11-12, the rack 35 may include aplurality of brackets, such as L-channels 52 attached to the verticalsupports 130. The brackets 52 may extend substantially the depth of eachstorage location 50. In this way, each storage location 50 may bedefined as the area extending between adjacent vertical supports andextending upwardly from adjacent a pair of horizontal supports elements52 to a point adjacent an upper pair of horizontal supports or the topof the rack.

Additionally, as shown in FIG. 11, each storage location 50 may beconfigured so that the containers 80 project inwardly toward the aisleso that the inner end of the container projects inwardly beyond thevertical supports. In other words, the containers 80 may be stored inthe storage locations 50 so that the inner edge of the container (withrespect to the aisle 20) overhands into the aisle.

Referring now to FIG. 9, the racks may be configured so that one or moreof the storage locations 50 is deep enough to accommodate a plurality ofcontainers. For example, one or more of the storage locations are atleast approximately twice as deep as the storage containers 80 so thattwo storage containers can be stored, with one storage container storedbehind the other storage container. It should be understood that thestorage locations may be configured to accommodate any number of storagecontainers. For instance, the racks 35, 40 may be configured so that oneor more of the storage locations can accommodate three containers, sothat the containers are three-deep. In such an embodiment, the storagelocation 50 is approximately three times as deep as the length of thestorage container 80. Similarly, the depth of the rack can be increasedto be approximately “n” times the length of the storage containers toaccommodate “n” storage containers stored “n” deep, wherein “n” is aninteger.

In the exemplary arrangement of FIG. 9, the system is illustrated inconnection with an arrangement for storing containers in a “n” deeparrangement, in which “n”=2. Although the apparatus may include only asingle rack on one side, in FIG. 9, the system is illustrated with tworacks, front rack 35 and rear rack 40. Additionally, each rack isillustrated as being configured to accommodate containers in a two-deeparrangement. However, it should be understand that the racks 35, 40 donot need to be configured to accommodate the same number of containers.For instance, the front rack may be configured as a two-deep rack andthe rear rack 40 may be configured as a single deep rack.

In the following discussion, the storage locations will be describedrelative to the arrangement illustrated in FIGS. 8-9. Each storagelocation 50 includes a first (aisle facing or inner) storage region 55and a second (outer) storage region 57. Each of the inner and outerstorage regions 55, 57 is configured to accommodate a container 80. Theinner storage regions 55 are adjacent the aisle 20. The outer storageregions 57 are behind the inner storage regions 55, so that the innerstorage location separates the outer storage location from the aisle 20and the vehicle 200. In the present instance, the inner storage region55 has a depth that is approximately the same as the length of acontainer 80. Similarly, the outer storage region 57 has a depth that isapproximately the same as the length of the container 80. The outerstorage regions 57 may be considered remote or distal storage regionsbecause they are separated from the aisle by an inner storage region. Ina system having a depth of greater than two, the remote regions includestorage regions that are separated from the aisle by an inner storageregion and one or more outer storage regions.

As discussed previously, embodiments of an ASR system consistent withthe present disclosure may include a plurality of vehicles 200 that areconveyed to the storage locations to transfer items to and from thestorage locations. In particular, the vehicles 200 may include aloading/unloading mechanism to transfer items into a storage location 50or withdraw a container from the storage location. In an embodiment inwhich the storage containers are stored two or more deep, the system isconfigured so that the vehicles are able to retrieve containers storedin one of the remote storage regions of a storage location. Forinstance, each vehicle may include a loading element that extendsoutwardly to a remote storage region to engage a storage container in aremote storage region to move the container to an inner storage regionand/or to load the container onto the vehicle from the remote storageregion. Alternatively, a separate mechanism may be utilized to movecontainers from a remote storage region to an inner storage region. Forinstance, the rack may include a drive mechanism operable to drive acontainer toward the aisle from a remote storage location. The drivemechanism may be separately powered or may interact with a drivemechanism from one of the vehicles. Yet another alternative is tointerconnect a container in a remote storage region with an adjacentcontainer such that displacing one of the containers displaces bothcontainers. For instance, a container in a remote storage region may bereleasably connected with a container in an inner storage region. Whenthe container in the inner storage region is moved toward the aisle 20,the container in the remote storage region is displaced toward the innerstorage region.

Referring now to FIGS. 11-14, the storage containers 80 are configuredto connect with adjacent containers. In particular, the storagecontainers are configured to releasably connect with one or moreadjacent containers. For instance, as shown in FIG. 13, a releasableconnector 90 connects two adjacent containers 80A, 80B. The releasableconnector selectively connects the two containers. In this way,displacing container 80A horizontally also displaces container 80B.Additionally, the releasable connector 90 may inhibit relative motion inone direction, while allowing relative motion in a second or transversedirection. For example, the connection may connect containers 80A and80B so that horizontal displacement of one container also displaces theother container. At the same time the releasable connector may beconfigured to allow vertical displacement of one container relative tothe other. In the embodiment illustrated in FIGS. 11 and 13-14, thereleasable connector 90 is configured to permit relative verticaldisplacement to connect or disconnect two adjacent containers asdiscussed further below.

In the following discussion, the details of an exemplary storagecontainer 80 are provided. The container 80 may be similar to a cartonor box without a lid, so that an operator can easily reach into thecontainer to retrieve an item at the picking station. Although thepresent system is described as using containers, it should be understoodthat any of a variety of storage mechanisms can be used, such as palletsor similar platforms. Accordingly, in the following discussion, the termcontainer is intended to include items intended to store and/or supportitems, including, but not limited to a pallet, platform, tray, carton,box, receptacle or similar structure.

The storage container 80 may be rectangular prism having a generallyplanar bottom 83. The bottom 83 is substantially horizontal, forming aplatform for receiving items. The container may also include a pluralityof generally vertical walls extending upwardly from the bottom 83. Forinstance, the container 80 may include generally parallel side walls 82.The container may include a forward wall 84 that projects upwardly fromthe bottom 83. The front face may extend between side walls 82 toconnect the side walls. Additionally, the container may include a rearwall 86 that projects upwardly from the bottom. The rear wall 86 may begenerally parallel with the front wall 84. The rear wall 86 may alsoextend between the side walls 82 to connect the side walls. Accordingly,the walls (82,83,84,86) of the container 80 define an interior space inwhich items can be stored.

The containers 80 may include one or more elements configured tocooperate with the vehicles to transfer the containers onto or off ofthe vehicles 200. For instance, the containers may include a hook,detent, socket, or other physical structure configured to cooperate withthe vehicles. In the present instance, the containers may include aretention slot or groove 88 configured to cooperate with aloading/unloading element 212 of the vehicles. The retention groove 88may be formed in the underside of the container 80, below the bottom 83.The retention groove 88 may be spaced rearwardly from the front face 84of the container as shown in FIGS. 11 and 13. The retention groove 88may extend substantially the entire width of the container. The groovemay also have open ends on both sides 82 as shown in FIGS. 11 and 13 sothat the groove is a through slot. As shown in FIG. 13, the groove mayhave a depth that is deeper than the thickness of the loading/unloadingelement 212 of the vehicle 200 so that the loading/unloading elementremains nested within the groove to drive the container inwardly oroutwardly when the loading/unloading element is displaced horizontally.The container 80 may also include a second groove or slot 88 adjacentthe rearward wall 86. The second groove may be configured substantiallysimilarly to the first wall and may be formed adjacent the rearwardwall, spaced forwardly from the rearward wall 86.

Referring to FIGS. 13-14, a releasable connector 90 is illustrated forreleasably connecting adjacent containers 80A, 80B. The connector 90 mayfacilitate displacement of one of the containers from a remote storagelocation 57 to an inner storage location 55. The releasable connector 90may be cooperating hooks or latches. For instance, the releasableconnector 90 may be formed of a pair of cooperable connectors 92B, 96A.A forward connector 92 may be connected with the forward end 84 of thecontainer 80 and a rearward connector 96 may be connected with therearward end of the container 80. In this way, the forward connector 92Bof a first container 80B is releasably connectable with the rearwardconnector 96A of a second container 80A to connect the two containers.In one embodiment, the forward connector 92 is a hook in the form of atongue extending downwardly generally vertically (see 92B in FIG. 14).The forward connector 92 projects downwardly from a recess adjacent theforward end of the container. In the present instance, the forwardconnector is an L-shaped bracket. The L-shaped bracket may have a bodyportion rigidly and fixedly connected with the bottom of the container.For example, the body portion of the forward connector 92 may extendsubstantially horizontally and may be affixed to the container by afastener extending through the connector 92 and into the container. Thetongue 94 of the forward connector may project transverse the bodyportion so that the tongue projects downwardly to form a vertical hookor flange that engages the second connector 96. As shown in FIG. 13, theforward connector may be connected to the container forwardly of thegroove 88 used to engage the loading/unloading mechanism 212 of thevehicle.

The rearward connector 96 may be a second hook that cooperates with thefirst hook 92. The rearward connector 96 may project rearwardly from therearward end of the container 80. In the present instance, the secondconnector 96 incorporates a hook or flange that projects verticallyupwardly. Specifically, the second connector 96 may comprise a groove orchannel 98 configured to receive the tongue 94 of the first connector92. The channel 98 may be connected to a rearward end 86 of thecontainer 80 so that the channel projects rearwardly from the rearwardend. The second connector may have a body portion rigidly and fixedlyconnected with the bottom of the container. For example, the bodyportion of the rear connector 96 may be a generally flat portionextending substantially horizontally and may be affixed to the containerby a fastener extending through the connector 96 and into the container.

As shown in FIG. 13, the tongue 94B of the forward connector 92B of afirst container 80B is inserted into the slot 98A of the rearwardconnector 96A of the second container 80A to connect the first andsecond containers. As discussed further below, the connection betweenthe two containers allows the containers to move together when one ofthe containers is displaced. In this way, pulling a first container froman inner storage location onto a vehicle pulls a connected containerfrom a remote storage location toward an inner storage location.

Pick Station

As described previously, an ASR system constructed according toembodiments consistent with the present disclosure, as system 10 of FIG.1, may be configured so that the vehicles 200 retrieve items from thestorage locations 50 and transport the items to the pick station 300.Returning to FIGS. 1, 2A, and 2B, the pick station 300 will be describedin greater detail.

In one mode of operation, system 10 is used to retrieve items needed tofill an order. The order may be an internal order, such as parts neededin a manufacturing process in a different department, or the order maybe a customer order that is to be filled and shipped to the customer.Either way, the system automatically retrieves the items from thestorage areas and delivers the items to the picking station so that anoperator can pick the required number of an item from a container. Afterthe item is picked from a container, the vehicle advances so that thenext item required for the order is advanced. The system continues inthis manner so that the operator can pick all of the items needed for anorder.

In the present instance, the pick station 300 is positioned at one endof the array of storage locations. However, it may be desirable toincorporate multiple pick stations positioned along the track 110. Forinstance, a second pick station can be positioned along the opposite endof the array of storage locations. Alternatively, multiple pick stationscan be provided at one end. For instance, a second pick station may bepositioned above a first pick station at one end of the aisle.

The pick station 300 may be configured so that the vehicle travelsupwardly to present the contents to the operator so that the operatorcan more easily retrieve items from the container 80. Referring to FIGS.1-2, at the picking station the track includes a curved section 315 thatbends upwardly and away from the operator. In this way, the vehiclemoves upwardly and then stops at a height that facilitates the operatorremoving items from the container. After the operator removes items fromthe container, the vehicle moves laterally away from the operator andthe vertically to the upper horizontal rail 135.

The system can be configured so that the vehicles tilt at the pickstation 300 thereby making it easier for the operator to retrieve itemsfrom the container. For instance, as the vehicle approaches the pickstation, the controller may control the vehicle so that the rearward setof wheels continue to drive after the forward set of wheel stop. Thisraises the rearward edge of the vehicle (from the perspective of theoperator). After the operator picks the items from the container, theforward set of wheels (relative to the operator) drive first, therebylevel off the vehicle. Once leveled, the four wheels drivesynchronously.

Although the vehicles may be tilted by controlling operation of thevehicles, if the wheels of the vehicles positively engage drive elementsin the track, such as the toothed wheels 220 that mesh with teeth in thetrack as described above, the wheels 220 may bind if the rear wheels aredriven at a different rate than the forward wheels. Accordingly, thetrack system may be modified so that the track moves to tilt thecontainer toward the operator.

With continued reference to FIGS. 1 and 2, the details of the tracksystem in the picking station 300 will be described in greater detail.At the end of the columns of storage locations, the track curvesoutwardly away from the vertical columns of the system to form thecurved, transitional track segments 315 of the pick station 300. Thetrack sections of the pick station include parallel forward tracksections that support and guide the forward axle 215 of the vehicles 200and parallel rearward track sections that support and guide the rearaxle 215 of the vehicles. The forward track sections extend verticallyupwardly and then curve back toward the vertical columns of storagelocations. The rearward track sections are substantially parallel to theforward track sections and curve substantially similarly to the forwardtrack sections. In this way, the forward and rearward track sectionsguide the vehicles so that the vehicles can maintain a substantiallyhorizontal orientation as the vehicles are driven along the curved track315.

The rearward track sections may be configured so that the rearward axleof the vehicle 200 can be lifted while the vehicle is stopped at thepick station 300. By lifting the rearward axle of the vehicle 200, thecontainer on the vehicle is tilted to present the contents of thecontainer to the operator to facilitate the picking process.

The pick station 300 may include a plurality of items to improve theefficiency of the pick station. For instance, the pick station mayinclude a monitor to display information to aid the operator. As thevehicle approaches the pick station, the system 10 may displayinformation such as how many items need to be picked from the containerfor the order. Additionally, since the operator may pick items formultiple orders, the system may display which order(s) the item is to bepicked for, in addition to how many of the item are to be picked foreach order. The system may also display information such as how manyitems should be remaining in the container after the operator picks theappropriate number of items from the container.

One feature of the system as described above is that the orientation ofthe vehicles does not substantially change as the vehicles move fromtravelling horizontally (along the upper or lower rails) to vertically(down one of the columns). Specifically, when a vehicle is travellinghorizontally, the two front geared wheels 220 cooperate with the upperor lower horizontal rail 135 or 140 of the front track 115, and the tworear geared wheels 220 cooperate with the corresponding upper or lowerrail 135 or 140 of the rear track 120. As the vehicle passes through agate and then into a column, the two front geared wheels engage a pairof vertical legs 130 in the front track 115, and the two rear gearedwheels engage the corresponding vertical legs in the rear track 120. Itshould be noted that when it is stated that the orientation of thevehicles relative to the horizon do not change, this refers to thetravel of the vehicles around the track. Even though the vehicles maytilt relative to the horizon at the picking station, the vehicles arestill considered to remain in a generally constant orientation relativeto the horizon as the vehicles travel along the track 110.

As the vehicle travels from the horizontal rails to the vertical columnsor from vertical to horizontal, the tracks allow all four geared wheelsto be positioned at the same height. In this way, as the vehicle travelsalong the track it does not skew or tilt as it changes between movinghorizontally and vertically. Additionally, it may be desirable toconfigure the vehicles with a single axle. In such a configuration, thevehicle would be oriented generally vertically as opposed to thegenerally horizontal orientation of the vehicles described above. In thesingle axle configuration, the weight of the vehicles would maintain theorientation of the vehicles. However, when using a single axle vehicle,the orientation of the storage locations would be re-configured toaccommodate the vertical orientation of the vehicles.

Operation

Once the central controller determines the appropriate storage location50 for the item, the route for a vehicle leaving the pick station 300may be determined. Specifically, the central controller may determinethe route for the vehicle and communicates information to the vehicleregarding the storage location into which the item is to be delivered.The central controller may then control the operation of the vehicle toactuate gates along the track as necessary to direct the vehicle to thestorage location into which the item is to be delivered. Once thevehicle reaches the appropriate storage location, the vehicle stops atthe storage location 50 and the container is displaced into theappropriate storage location. For example, the vehicle may be stopped atthe appropriate storage location 100 and the onboard controller on thevehicle may send an appropriate signal to the vehicle to drive the chain214, which advances the bar 212. Since the bar 212 is engaged in theslot 88 in the container, the bar drives the container off the vehicleand into the appropriate storage location.

After discharging the item, the vehicle 200 may travel to a secondstorage location to retrieve the next item to be transported to thepicking station. After retrieving the item, the vehicle 200 may traveldown the vertical legs 130 of the column until it reaches the lower rail140. Gates may direct the vehicle along the lower rail, and the vehiclemay follow the lower rail to return to the pick station 300 to deliveranother item.

If the vehicle 200 delivers a container to an empty storage location,then the operation of the vehicle proceeds as described above.Similarly, if the vehicle retrieves a container 80 that is not connectedwith another container, then the operation of the vehicle proceeds asdescribed. In particular, the vehicle stops adjacent the container. Theloading/unloading mechanism advances into engagement with the containerand then the loading/unloading mechanism pulls the container onto thevehicle. In contrast, the operation of the vehicle is modified if thevehicle carries a container to be placed in a storage location thatalready contains a container. Similarly, the operation of the vehicle ismodified if the vehicle is retrieving a container attached to acontainer in a remote storage location.

Referring now to FIGS. 9 and 10A-10H, the operation of vehicle inretrieving a container from a storage location having “n” deepcontainers will be described. FIG. 9 illustrates an exemplary embodimentin which two racks 35, 40 of storage containers 80 are illustrated. Theracks 35, 40 are separated from one another by an aisle and the vehicle200 travels within the space between the racks. In the illustratedembodiment, the rack includes storage locations that have a depthsufficient to store two storage containers. The portion of the storagelocation that accommodates the storage container adjacent the aisle isreferred to in this discussion as the inner cell and is designated 55.The portion of the storage location behind the inner cell 55 is referredto as the remote cell and is designated 57.

In the illustrated embodiment, each container includes a front connector92 connected to the front end of the container and a rear connector 96connected to a rear end of the container. The front connector of thecontainer in the remote cell connects with rear connector of thecontainer in the inner cell to create a releasable connection designated90.

In FIG. 9, storage container 80A is stored in a remote cell behindstorage container 80B that is stored in an inner cell. Containers 80A,80B are releasably connected to one another by a connector, such asconnector 90. The containers 80A, 80B are generally aligned from ahorizontal perspective. The vehicle 200 is stopped at a positionadjacent the storage location that houses container 80A. The vehicle 200is empty (i.e. no container is loaded on the vehicle). The load/unloadmechanism 210 engages the container 80A as shown in FIG. 9. For example,as shown in FIGS. 11 and 12, the front edge of the container 80 mayextend into the aisle beyond the track (e.g. vertical track sections130). In particular, the transfer groove 88 of the container 80 mayextend into the aisle. The load bar 212 extends outwardly toward thecontainer, away from the platform of the vehicle until the load bar isinserted into the transfer groove 88.

Referring to FIG. 10A, the load mechanism pulls the container 80A ontothe vehicle 200. As the container 80A in the inner cell is pulled ontothe vehicle, the container 80A pulls the container 80B in the remotecell toward the inner cell. In particular, the connector 90 connects theinner and remote containers 80A, 80B so that the containers movehorizontally together.

Referring to FIG. 10B, vehicle continues to displace the container 80Aonto the platform of the vehicle until the container is clear of thecontainer in the storage location above the container. The displacementof container 80A pulls the remote container 80B into the inner cell sothat container 80B has taken the place that container 80A had in therack. It can be seen in FIG. 10B that by pulling container 80B into theinner cell, the remote cell 57 behind container 80B is now vacant.

As described above, the loading mechanism 210 of the vehicle loads theinner container 80A onto the vehicle, which in turns displaces theremote container 80B horizontally until the remote container is movedinto a different storage locations, which in this instance is an innercell. Continued displacement of the container 80A onto the vehicle wouldpull container 80B into the aisle and potentially onto the vehiclebecause the two containers remain connected. Accordingly, once thecontainer 80B is displaced into the new storage location (i.e. the innercell), the releasable connection 90 disconnects to thereby disconnectthe two containers 80A, 80B.

Containers 80A, 80B may be disconnected in a variety of ways, dependingon the mechanism that interconnects the containers. As noted previously,the connectors 92, 96 may be any of a variety of connectors that providea releasable connection between two containers. The connectors may bemechanical or electro-mechanical. For example, the connectors 92, 96could be magnetic elements, one of which may comprise an electro-magnet.The electro-magnet may be de-energized to disconnect the containers tofacilitate relative motion of the first container relative to the secondcontainer. Alternatively, as described above, the connectors 92, 96 maybe mechanical connectors, such as a pair of hooks or a tongue and groovearrangement. Accordingly, to disconnect the containers 80A, 80B, theconnectors 92, 96 are disengaged. In one embodiment, the connectors 92,96 are disengaged by displacing one of the containers verticallyrelative to the other container.

Referring to FIG. 10C, once the first container 80A is loaded onto thevehicle so that the container 80A is clear of the containers immediatelyabove it or below it in the column, the container 80A is displacedvertically to disconnect container 80A from container 80B. As shown inFIGS. 13-14, the tongue 94B of connector 92B may project downwardly intothe groove 98A of connector 96A. Therefore, the vehicle moves downwardlyto vertically displace container 80A downwardly until the tongue 94B ofconnector 92B disengages the groove 98A as shown in FIG. 14. In thisway, displacing the vehicle 200 vertically disconnects container 80Afrom container 80B. It should be understood, that the connectors 92, 96may be configured differently so that the connectors are disconnected bymoving the vehicle upwardly, rather than lowering the vehicle.

Referring now to FIG. 10D, after the first container 80A is disconnectedfrom the second container 80B, the container 80A is displacedhorizontally on the vehicle away from the second container. The firstcontainer is displaced horizontally until is centered within the aislesuch that the container is clear from interfering or engaging any of thevehicles in the rack when the vehicle moves vertically upwardly ordownwardly in the column. Once the container 80A is completely loadedonto the vehicle, the vehicle may advance toward the picking station 300or other transfer location or to a different storage location. Forexample, the vehicle may move down to the lower horizontal rail and thenalong the horizontal rail to deliver container 80A to the pickingstation 300. Alternatively, the container 80A may be transported toanother storage location and unloaded into the storage location.

The details of the steps of unloading the container 80A on vehicle 200into a storage location in which a third container designated 80C islocated are described below in connection with FIGS. 10E-10H. Thevehicle 200 moves into position adjacent an inner cell in rack 40 inwhich container 80C is stored. The container 80A is unloaded from thevehicle toward the third container 80C. As the container 80A isunloaded, the container 80A pushes the third container 80C deeper intothe storage location in the rack. Doing so displaces container 80Chorizontally from the inner cell into the remote cell 57. During theprocess of unloading the first container 80A and displacing container80C, the first container 80A is connected to the third container 80C. Asdescribed previously, the connectors of the two containers may beconnected in a variety of ways. In the present instance, the containersare connected by moving one of the containers relative to the other.Specifically, the first container 80A is displaced vertically relativeto the third container 80C to connect the two containers.

Referring again to FIG. 10E, to unload the first container 80A, thevehicle is displaced along the track until the first container 80A isdisposed vertically higher than the third container 80C. In particular,the vehicle is driven to a position adjacent the container so that thefront connector of the first container is positioned above the rearconnector of the third container 80C. The first container is thendisplaced horizontally toward the third container 80C to partiallyunload the container from the vehicle, as shown in FIG. 10F. In thepresent instance, the first container is displaced until the frontconnector of the first container is aligned with the rear connector ofthe third container 80C. In particular, the unloading mechanism 210 ofthe vehicle displaces the container 80A horizontally until the tongue 94of the front connector 92 is aligned with the groove 98 of the rearconnector 96 on the third container 80C.

Once the connectors of container 80A and 80C are aligned, the vehiclemoves vertically to connect the containers. Specifically, referring toFIG. 10G, the vehicle moves downwardly to horizontally align containers80A and 80C and to interconnect the two containers. Once the firstcontainer 80A is aligned horizontally with the storage location, thefirst container is unloaded from the vehicle into the storage locationas shown in FIG. 10H. For instance, in the present embodiment, theloading/unloading mechanism of the vehicle drives the first container80A off of the vehicle and into the inner cell in which the thirdcontainer 80C was located. As the first container is driven into theinner cell, the first container 80A pushes the third container 80Cdeeper into the storage location so that the third container is movedinto the remote cell (designated 57 in FIG. 10G).

As described above, the first container 80A is moved into positionadjacent the third container 80C. The two containers are then connectedbefore unloading the first container into the storage rack. In this way,the containers are linked so that subsequently, the third container inthe remote cell can be pulled toward the aisle when the first container80A is retrieved (see e.g. FIGS. 10A-10D and description above).However, it should be appreciated that the containers do not need to beconnected in order to unload the first container and move the thirdcontainer into the remote cell. Specifically, since the first container80A pushes the third container 80C rearwardly into the rear cell, thecontainers do not need to be connected prior to unloading the firstcontainer. Therefore, depending on the configuration of the front andrear connectors, the containers may be connected to one another afterthe first container is unloaded from the vehicle.

Accordingly, as described above, the system may be configured toincorporate multi-depth storage locations in which containers are storedbehind one another in a common horizontal storage location. Thecontainers in a common horizontal storage location may be interconnectedso that retrieving one of the containers in the common storage locationdisplaces the other containers in the common storage location forwardlytoward the vehicle. In the above description, the operation has beendescribed in which a first container is loaded onto a delivery vehicle,thereby pulling a container from a remote cell into an inner cell sothat the container can be retrieved from the inner cell. The vehicle canthen deliver the first container to a different storage locations andthen return to retrieve the second container that was displaced into theinner cell. Alternatively, in certain instance, a storage locationhousing two containers (such as containers 80A and 80B shown in FIG. 9)may be located across from an open storage location vertically andhorizontally aligned with the two containers. In such an instance, thefirst container 80A may be loaded onto the vehicle, thereby pulling thesecond container toward the vehicle. Rather than disconnecting the twocontainers as described above, the first container 80A is furtherdisplaced horizontally to unload the container into a storage locationin the opposing rack. As the first container 80A is unloaded into thestorage location, the second container 80B is pulled onto the vehicle.The second container can then be disconnected from the first containerso that the vehicle can deliver the second container to the pickingstation or a different storage location. For instance, the vehicle canbe displaced vertically to disconnect the second container from thefirst container.

In the foregoing description, a system is described in which containersare stored in multi-depth storage locations. A container in a remotecell of a multi-depth storage location may be retrieved by a vehiclefirst retrieving a container that is in front of the container in theremote cell. The retrieved container is then transported away by thevehicle. The retrieved container may then be stored in a differentlocation so that the vehicle can return to retrieve the container thatwas located in the remote cell. Alternatively, a first vehicle mayretrieve the container that is in front of the container in the remotecell and a second vehicle may come and retrieve the vehicle that waslocated in the remote cell.

Multiple Aisle Configurations

Turning now FIGS. 15A to 15F, there are shown respective side elevationviews of a multiple aisle ASR system 1500 constructed in accordance withan alternate embodiment consistent with the present disclosure, theviews of FIG. 15A to 15F collectively illustrating phases of aninter-aisle container transfer operation. Such a transfer operationenables any container to be retrieved from any storage location of anyrack structure, as rack structures 1510, 1512, 1514 or 1514, anddelivered to any pick station, as existing pick stations 1530 and 1532located at positions PS1 and PS1, respectively, or any future pickstations located, for example, at position PS3.

FIGS. 15A to 15F exemplify an operation by which container 1580Acontaining one or more items required for retrieval at pick station 1532is transferred from a storage region accessible only to a vehicle, asvehicle 200A, movable within aisle 1520A to a storage region accessibleonly to a vehicle, as vehicle 200B movable within aisle 1520B. To thisend, the vehicle 200 depicted in FIG. 15A is shown conveying container1580A from the initial, solid line position near the top of the aisle,to the dotted line position adjacent to a completely vacant storagelocation 1550 having open storage regions 1555 and 1557. The selectionof a completely vacant storage location as location 1550 minimizes thenumber of container placement operations needed to affect theinter-aisle transfer.

As shown in FIG. 15B, the container 1580A is first transferred to thestorage region 1550 which faces aisle 1520A. As described in connectionwith FIGS. 1-14, and shown in FIG. 15C, a container 1580B is withdrawnfrom an aisle facing storage location of rack structure 1510. For aquicker transfer operation, the container 1580B is selected based on itsproximity to the storage region 1550 and the ability to move thecontainer 1580B without first having to decouple it from a linkedcontainer behind it, as container 1580C. In the instant example, anuncoupling operation as described in connection with FIGS. 9 to 10G isperformed such that container 1580B is decoupled from container 1580Cbefore moving the former and latter into the positions shown,respectively, in FIG. 15D. In the process, container 1580A advances fromthe storage region 1555 facing aisle 1520A into the storage region 1557facing aisle 1520B.4

In FIG. 15E, it can be seen that second vehicle 200B is aligned with thestorage region 1557. By operation of the container extractor systempreviously described, container 1580A is withdrawn from storage region1557 and, at the same time, the container 1580B behind it advances intothe storage region 1557. Thereafter, the vehicle moves container 1580Ato pick station 1532, as shown in FIG. 15F. As will be readilyappreciated by those skilled in the art, transfers in the reversedirection (e.g., from pick station 1532 to a storage location of rack1510) is achieved by reversing the operation described above. Likewisethe process may be repeated in order to permit delivery of container1580A to a pick station at location PS3.

FIG. 16 depicts yet another multiple aisle ASR system indicatedgenerally at 1600. Aisle to aisle transfer of containers is simplifiedby using an alternating arrangement of n- and 1-deep storage locations,with racks 1610, 1614 and 1618 defining two back-to-back storage regionsand 1612 and 1616 defining a single deep storage region through whichcontainers, as container 1680A, may pass in either direction to permit atransfer or pick operation at any of pick stations 1630, 1632, 1634 or1636. As shown in FIG. 16, each rack may include storage locations thatare deep enough to accommodate multiple containers 1680 such as racks1610, 1614 and 1618. Alternatively, each rack may include storagelocations that are only deep enough to accommodate a single container1680, such as racks 1612 and 1616. The depth of each rack may varydepending upon the particular application. However, regardless of thedepth of the racks, each aisle includes tracks 130 on each side tosupport and guide the vehicles 200. Accordingly, racks that are betweentwo aisles include track on each side of the rack. For instance, aisle1620A is formed between rack 1610 and rack 1612. Rack 1610 is an endrack. Therefore, a first track 110A is attached to the side of the rackfacing the aisle. Rack 1612 is an inside rack that is between aisle1620A and 1620B. Accordingly, rack 1612 includes a first track 110Battached to the side aisle 1620A and a second track attached to the sidefacing aisle 1620B. It should be noted that the track illustrated inFIG. 16 is a fragmentary view of a portion of a vertical leg, such asleg 130 illustrated in FIG. 3A. It should be understood that the tracks110A, 1008, 110C, 110D in FIG. 16 may be configured similarly to thetrack illustrated in FIG. 3a , having a plurality of vertical tracksinterconnecting a plurality of horizontal tracks. Additionally, as notedpreviously, the track may be designed in a variety of configurations.Configured as illustrated in FIG. 16, vehicle 200A travels in aisle1620A and is supported and guided on one side by track 110A and theother side by track 110B. The vehicle is operable to transfer storagecontainers, such as container 1680A between the vehicle and either rack1610 or rack 1612. Similarly, vehicle 200B travels in aisle 1620B and issupported and guided on one side by track 110C and the other side bytrack 130D. In this way, vehicle 200B is operable to transfercontainers, such as container 1680B between vehicle 200B and rack 1612or rack 1614. Additionally, containers can be transferred betweenadjacent aisles so that a container 1680 from a first aisle can betransferred to a second aisle so that the item can be delivered to thepick station at the second aisle.

Referring now or FIG. 17, an alternate embodiment of an automatedmaterial handling system 1700 is illustrated. The system includes aplurality of racks 1710, 1712, 1714, 1716. Each rack includes aplurality of storage locations 1757. As described above, the rack ofstorage locations may be configured as an array of storage locations,such as an array of columns or an array of rows. An aisle is formedbetween adjacent racks, such as aisle 1720A, 1720B and 1720C. The system1700 includes a plurality of vehicles that travel within the aisles. Asdiscussed previously, each vehicle is guided by a track within theaisle. For example, a first track 110A located adjacent a first side ofrack 1710 guides and supports a first end of vehicle 200A in aisle 1720Aand a second track 110B adjacent a first side of rack 1712 guides andsupports a second end of vehicle 200B in aisle 1720A. Similarly, rack1712 includes a second track 110C positioned adjacent the second side ofrack 1712. The second track positioned adjacent rack 1712 forms aportion of the track supporting vehicle 200B in aisle 1720B. In thisway, racks positioned between two aisles include track on both sides ofthe rack, such as rack 1712, which is positioned between track 110B and110C, and rack 1714, which is positioned between track 110D and 110E.

As shown in FIG. 17, a container can be transferred between adjacentaisles so that a container stored in one aisle can be transferred to adifferent aisle so the container can be conveyed to the picking station.In this way, each picking station has access to all the container in allthe aisles. For example, in FIG. 17 a container 1780 is originallystored in location 1757D, which is in a third aisle, designated 1720C.Vehicle 200C operates within the third aisle 1720C. Therefore, vehicle200C is able to move in the third aisle along tracks 110E, 110F so thatvehicle 200C is aligned with storage location 1757D. Container 1780 isthen transferred onto vehicle 200C (note that the container 1780 isshown in dashed lines on vehicle 200C because the container issubsequently transferred to vehicle 200B as described below). Thevehicle 200C then transfers the container 1780 to a storage location inrack 1714, which is a rack that is between the third aisle 1720C and asecond aisle 1720B. In some situations, the vehicle may be able totransfer the container directly to the opposing rack 1714. However, inthe example illustrated in FIG. 17, the vehicle moves upwardly towardlocation 1757C in rack 1714.

After the container 1780 is moved from the first rack to the secondrack, vehicle 200B in the second aisle 1720B may retrieve the container.As discussed above, the vehicle retrieves the container 1780 bytraveling along tracks 110C and 110D until the vehicle is aligned withstorage location 1757C. The container is then transferred onto thesecond vehicle 200B as shown in FIG. 17. The vehicle is operable totransport the container to picking station 1732, which is positionedalong aisle 1720B. Additionally, the vehicle may deliver item 1780 tostorage location 1757B, so that vehicle 200A in aisle 1720A can retrievethe container from location 17578. In this way, vehicle 200A can deliverthe container to picking station 1730. Additionally, after deliveringthe item to picking station 1730, the vehicle 200A may store thecontainer in open storage location 1757A in rack 1710.

From the foregoing, it should be understood that the system may includea number of racks forming one or more aisles in which vehicles travel.If the system includes two or more aisles, the racks may be configuredso that one or more racks is adjacent two aisles. Therefore, an itemtransferred to such rack from a vehicle in one aisle can be retrieved bya vehicle in an adjacent aisle. In some embodiments, the racks that areadjacent two aisles are n-deep racks, meaning that storage locations inthe racks are deep enough to accommodate a plurality of storagecontainers. In some embodiments, the racks that are adjacent two aislesare single depth racks, meaning that the storage locations in the racksare deep enough to accommodate a single storage container.

It will be recognized by those skilled in the art that changes ormodifications may be made to the above-described embodiments withoutdeparting from the broad inventive concepts of the invention. It shouldtherefore be understood that this invention is not limited to theparticular embodiments described herein, but is intended to include allchanges and modifications that are within the scope and spirit of theinvention as set forth in the claims.

What is claimed is:
 1. A material handling system for storing orretrieving a plurality of Items, comprising: a first rack of storagelocations; a second rack of storage locations spaced apart from thefirst rack forming a first aisle between the first and second racks; athird rack of storage locations spaced apart from the second rackforming a second aisle between the second and third racks; a firstvehicle operable within the first aisle to deliver items to and retrieveitems from the storage locations in the first and second storage racks;a second vehicle operable within the second aisle to deliver items toand retrieve items from the storage locations in the second and thirdracks; wherein the second rack is configured so that an item deliveredto the second rack by the second vehicle can be retrieved from thesecond rack by the first vehicle; wherein the storage locations of thefirst, second or third storage rack are configured to accommodate aplurality of storage containers; and wherein each of the storagecontainers comprise one or more releasable connector configured so thattwo storage containers can be connected to one another when the twostorage containers are stored within one of the storage locations. 2.The material handling system of claim 1 comprising: a first trackpositioned adjacent a first side of the first rack; a second trackpositioned adjacent a first side of the second rack, wherein the firstand second tracks guide the first vehicle in the first aisle; a thirdtrack positioned adjacent a second side of the second rack; and a fourthtrack positioned adjacent a first side of the third rack, wherein thethird and fourth tracks guide the second vehicle in the second aisle. 3.The material handling system of claim 2 wherein each of the first,second third and fourth tracks comprise a plurality of vertical tracksections interconnected by a plurality of horizontal track sections. 4.The material handling system of claim 1 wherein each of the first,second and third racks comprise an array of storage locations.
 5. Thematerial handling system of claim 1 wherein the first vehicle comprisesa first transfer mechanism configured to transfer items into the storagelocations in the second rack and the second vehicle comprises a secondtransfer mechanism configured to transfer items from the storagelocations in the second rack onto the second vehicle.
 6. The materialhandling system of claim 1 comprising: a first picking stationpositioned along the first aisle wherein the first aisle is configuredso that the first vehicle is able to retrieve items from the first orsecond racks and deliver the items to the first picking station; and asecond picking station positioned along the second aisle wherein thesecond aisle is configured so that the second vehicle is able toretrieve items from the second or third racks and deliver the items tothe second picking station, wherein the second rack is configured sothat items transferred to the second rack from the vehicle in the secondaisle may be retrieved by the first vehicle in the first aisle anddelivered to the first picking station so that items from the secondaisle can be transferred to the first aisle and delivered to the firstpicking station.
 7. The material handling system of claim 1 wherein thefirst and second vehicle are independently operable self-propelledvehicles.
 8. The material handling system of claim 1 wherein the firstvehicle is constrained to movement within the first aisle and the secondvehicle is constrained to movement within the second aisle.
 9. Thematerial handling system of claim 1 wherein the first rack comprises afirst array of bins disposed in a plurality of rows or columns, thesecond rack comprises a second array of bins disposed in a plurality ofrows or columns, and the third rack comprises a third array of binsdisposed in a plurality of rows or columns.
 10. A method for operatingan automated storage and retrieval system, comprising the steps of:conveying a first vehicle through a first aisle between a first rack ofstorage locations and a second rack of storage locations; conveying asecond vehicle through a second aisle between the second rack of storagelocations and a third rack of storage locations; transferring an itemfrom one of the storage locations on the first rack to the firstvehicle; transferring the item from the first vehicle to a storagelocation on the second rack; transferring the item from the second rackto the second vehicle; and transferring the item from the second vehicleto one of the storage locations on the third rack: wherein the step ofconveying a first vehicle comprises driving the first vehicle along afirst track adjacent the first rack and a second track adjacent thesecond rack and the step of conveying a second vehicle comprises drivingthe second vehicle along a third track adjacent a second side of thesecond rack and a fourth track adjacent the third rack.
 11. The methodof claim 10 wherein the step of conveying a first vehicle comprisesdriving the first vehicle around a first loop formed of a firstplurality of generally vertical tracks connected with a first pluralityof generally horizontal tracks and the step of conveying a secondvehicle comprises driving the second vehicle around a second loop formedof a second plurality of generally vertical tracks connected with asecond plurality of generally horizontal tracks.
 12. The method of claim10 comprising the step of conveying the second vehicle and the item to apicking station positioned along the second aisle and presenting theitem to an operator at the picking station.
 13. The method of claim 10wherein the item comprises a first storage container having a releasableconnector and the method comprises the step of releasably connecting thefirst storage container with a second storage container located in thesecond rack.
 14. The method of claim 13 comprising the step ofdisplacing the first storage container in the rack by displacing thesecond storage container connected to the first storage container. 15.The method of claim 14 comprising the step of disconnecting the secondstorage container from the second storage container.
 16. The method ofclaim 15 wherein the step of disconnecting comprises displacing thefirst container relative to the second container.
 17. The method ofclaim 10 wherein the step of transferring the item from the firstvehicle to a storage location on the second rack comprises the steps of:aligning the first vehicle with the storage location on the second rack;and operating a first transfer mechanism on the first vehicle totransfer the item to the storage location.
 18. The method of claim 17wherein the step of transferring the item from the storage location onthe second rack comprises the steps of: aligning the second vehicle withthe storage location; and operating a second transfer mechanism on thesecond vehicle to transfer the item to the second vehicle.
 19. Themethod of claim 10 wherein: the step of conveying a first vehiclethrough a first aisle comprises constraining the first vehicle to travelwithin the first aisle; and the step of conveying a second vehiclethrough a second aisle comprises constraining the second vehicle totravel within the second aisle.
 20. A method for operating an automatedstorage and retrieval system, comprising the steps of: conveying a firstvehicle through a first aisle between a first rack of storage locationsand a second rack of storage locations; conveying a second vehiclethrough a second aisle between the second rack of storage locations anda third rack of storage locations; transferring an item from one of thestorage locations on the first rack to the first vehicle wherein theitem comprises a first storage container having a releasable connector;transferring the item from the first vehicle to a storage location onthe second rack; transferring the item from the second rack to thesecond vehicle; and transferring the item from the second vehicle to oneof the storage locations on the third rack; wherein the method comprisesthe step of releasably connecting the first storage container with asecond storage container located in the second rack.
 21. The method ofclaim 20 comprising the step of displacing the first storage containerin the rack by displacing the second storage container connected to thefirst storage container.
 22. The method of claim 21 comprising the stepof disconnecting the second storage container from the second storagecontainer.
 23. The method of claim 22 wherein the step of disconnectingcomprises displacing the first container relative to the secondcontainer.